<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box{
            width:100px;
            height:100px;
            border: solid;
            background-image: linear-gradient(red,pink);
        }
        .diao{
            width:100px;
            height:100px;
            border: solid;
            background-image: linear-gradient(45deg,red,pink);
        }
        .six{
            width:100px;
            height:100px;
            border: solid;
            background-image: linear-gradient(90deg,red,pink);
        }
        .seven{
            width:100px;
            height:100px;
            border: solid;
            background-image: linear-gradient(to bottom left,black,red);
        }

        .sanjiaoxin{
            width: 0px;
            height: 100px;
            border: 100px solid;
            border-color: red transparent transparent;
        }


    </style>
</head> 
<body>
    <div class="box"></div>
    <div class="diao"></div>
    <div class="six"></div>
    <div class="seven"></div>
    <div class="sanjiaoxin"></div>
</body>
</html>